Retention Registers and Cell-Level Verification: Inputs and Outputs

Inputs and outputs contract

Inputs and Outputs for Retention Registers and Cell-Level Verification is anchored on Retention restore correctness across intended register list, wake-up latency bins, and voltage-corner pass rate.. Convert observations into mechanism-backed and owner-bound actions.

INPUTS
  - power-mode sequence and ownership context
  - seed, order, and configuration metadata
  - intent assumptions for transitions and crossings
  - assertion and coverage expectation envelope

OUTPUTS
  - evidence-backed failure classification
  - owner-signed mitigation proposal
  - validation matrix and rollback triggers
  - release recommendation

Ownership split

OWNERSHIP LAYERS - Retention Registers and Cell-Level Verification

+----------------------+--------------------------------+--------------------------------+
| Team                 | Primary responsibility         | Closure artifact               |
+----------------------+--------------------------------+--------------------------------+
| low-power verification owner | scenario intent and closure      | review rationale memo          |
| UPF/power intent owner | transition and boundary contract | timeline + assertion packet    |
| library characterization owner | regression signoff readiness     | validation matrix + risk note  |
+----------------------+--------------------------------+--------------------------------+

Low-power verification deep dive

Retention closure requires proving end-to-end state lifecycle through save, off, and restore windows.

Concept diagram

RETENTION LIFECYCLE

save request -> state capture -> power off -> power on -> restore -> traffic resume

Metric graph

RETENTION STABILITY

restore mismatch       █████
save timing defects    ████
stable wake cycles     ███████

Metrics and artifacts to collect

• retention save/restore timing report

• pre/post state diff matrix

• multi-cycle retention stress summary

• state-loss bug trend by mode

Mini case study

A corruption issue persisted until retention checks compared multi-cycle state snapshots rather than single wake events.

Debug branches

• Track save acknowledgement against actual state capture.

• Validate restore completion before functional traffic resumes.

• Run repeated sleep/wake cycles to expose drift.

Senior review question

Ask: what exact low-power transition boundary failed first, and which artifact proves the closure claim reproducibly?

Key takeaways

• Tie each LPV claim to a concrete transition boundary and one proving artifact.

• Prefer minimal reversible fixes with explicit owner and rollback criteria.

Common pitfalls

• Treating power-aware failures as random before boundary classification.

• Waiving X-prop failures before proving impact and root cause.

• Declaring closure without deterministic replay across key modes.

Handoff explanation

Inputs should include mode sequence, domain status, and control ownership context.

Outputs should include deterministic reproducer and acceptance boundaries.